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Anyone done hood vents?

52657 Views 89 Replies 1 Participant Last post by  Brad96
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As I've gotten more and more into open tracking over the past 10 years, I've learned a bit more about aerodynamics. Heat extractor vents in the hood have all sorts of benefits - reduce pressure under the hood (thereby reducing front end lift), improve airflow through the radiator, let some air out over the car rather than passing under the turbulent, non-aerodynamic underside, etc. The hood of the V looks like it wants to jump right off the car when you're blitzing down the straightaways at high speeds, so I'm sure some vents would be effective.

So, I've been planning to vent the hood of my Subaru for a while. I've done most of my track days in the Subie and I think it would benefit from some hood vents, particular for the improved flow through the radiator. I've accumulated a variety of OEM vents off Ebay and from junkyards as I looked around for a possible solution. In the end it looks like the Subie's going to get a '10 Mustang GT500 hood vent, but that leaves me with some other vents to play with.

In all the pics below the trailing edge of the painter's tape is about where the trailing edge of the fan shrouds is. No point in having the vents any farther forward than that.

Here are some vents taken from a 80s/90s Trans Am GTA. As you can see in the linked picture, the larger ones were actually run 180deg opposite of what I'm looking for, so I guess they must've fed the air intake rather than acting as vents. Whatevah!




Another option would be to put them so they're venting out to the sides. The shape of them doesn't really work out too well - they wouldn't line up with anything quite right.




And then there are the smaller, side-facing vents. I think these would be a nice, subtle touch mounted in basically the same place they were mounted on the GTA hood. Line them up with the character lines on the hood and I think they'd look almost OEM. The down side, of course, is that they're not very big.






An older picture with vents from a 80s turbo Lebaron:


And the biggest, baddest vents of them all, the Lumina Z34 vents.




On the Z34's hood they were mounted to vent to the side, kinda like the second set of pics I posted of the Trans Am vents. I could also do that on the V's hood, and it doesn't look bad, but for whatever reason I didn't take any pictures in that orientation.

Although I don't have them with this set, as installed on the Z34 they had rain drip trays beneath them. I would have to either get the drip trays, or make my own, otherwise the engine bay would get doused in the rain. But I could just pull the drip trays off for the track.

They line up almost perfectly - if I position the side of the vents parallel to the character line in the hood, the front edge of the vents lines up pretty well with the front of the hood. It's not perfect, but since they're set back almost 2ft I don't think it would matter.


In the more expensive, blingier realm, there's these CF vents from Anvil Auto. I don't have a pair of those handy, so I can't show you how they would look on the V's hood. :) Here's a nice shot of them on a classic Camaro:


They're about 8x12". In comparison, the Z34 louvers are about 7x20".
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Oh, and I'm not sure I'll ever really have the balls to do this. I guess if I can find a cheap-ass donor hood to cut as a test before I cut into the "real" hood?
Fast forward a few years and I finally sourced a cheap-ass donor hood. Checked the local Pick-n-Pull's inventory this morning and saw they had a 2006 CTS - the first time I've seen them have a CTS. I wanted to look at a couple things for my other 2 cars, so I headed over. The CTS's hood was not only intact and in decent shape, but someone had already removed it, so all the hard work was done! $55 out the door! (I occasionally look for them on Ebay, and even considered buying one a month or so ago, but about the lowest I've seen them priced was ~$250. Usually they're $300+ and then another $100+ freight on top of that, with the risk that the aluminum hood is going to get damaged along the way.)

It's not the right color, and the paint is pretty beat up along the center ridge (dragged on the gravel in the junkyard?), but for $55 I'm pretty happy. This project is still not real high on my list of automotive things to do, but having a hood to play with is definitely a step in the right direction.

Edit: Stock hood weighs ~24# (24.2# using the "me+hood" - "me alone" on my digital bathroom scale). That's complete - washer nozzles, "chrome" trim, hood liner, but no hinges.
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Fast forward a few years and I finally sourced a cheap-ass donor hood. Checked the local Pick-n-Pull's inventory this morning and saw they had a 2006 CTS - the first time I've seen them have a CTS. I wanted to look at a couple things for my other 2 cars, so I headed over. The CTS's hood was not only intact and in decent shape, but someone had already removed it, so all the hard work was done! $55 out the door! (I occasionally look for them on Ebay, and even considered buying one a month or so ago, but about the lowest I've seen them priced was ~$250. Usually they're $300+ and then another $100+ freight on top of that, with the risk that the aluminum hood is going to get damaged along the way.)

It's not the right color, and the paint is pretty beat up along the center ridge (dragged on the gravel in the junkyard?), but for $55 I'm pretty happy. This project is still not real high on my list of automotive things to do, but having a hood to play with is definitely a step in the right direction.

Edit: Stock hood weighs ~24# (24.2# using the "me+hood" - "me alone" on my digital bathroom scale). That's complete - washer nozzles, "chrome" trim, hood liner, but no hinges.
Do you plan on using the Lumina vents as well? I just started looking back into this. I may have an idea with carbon fiber if you are interested...
Yeah, I was planning on the Lumina vents. At some point since this thread started I found a set of the rain trays; they would have to be modified to be used, but they at least give me something to work with.

I'm all ears on the CF - shoot me a PM. :)
Living down here in East L.A. (eastern lower alabama) I really would like to do something to extract the heat also. It gets "surface of the sun hot" down here.... It looks like some drip pans would have to be fabbed up to fit around engine components and still be functional. Sounds like fiberglass time....
Found this on ebay, C7 Vette hood insert into a V1 hood...

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Link to the ad? Were they selling the hood, or the car, or the D3 windshield banner :p ? (If it's the windshield banner, I'm guessing that goes for $225 new from D3. :rolleyes:)

Edit: Found it - http://www.ebay.com/itm/CADILLAC-CT...es&hash=item339592b26a&vxp=mtr#ht_3231wt_1105. $325 for a hydro-dipped factory part. I haven't been able to find a part number for the factory part to look up what it costs without the hydro dipping..
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Link to the ad? Were the selling the hood, or the car, or the D3 windshield banner :p ? (If it's the windshield banner, I'm guessing that goes for $225 new from D3. :rolleyes:)

Edit: Found it - http://www.ebay.com/itm/CADILLAC-CT...es&hash=item339592b26a&vxp=mtr#ht_3231wt_1105. $325 for a hydro-dipped factory part. I haven't been able to find a part number for the factory part to look up what it costs without the hydro dipping..
Checking for you. I've already found it for $275 at another place so its basically the OEM part hydro dipped. APR makes it full carbon fiber as well for $470...

SLP also makes one for the Camaro with drip tray: http://www.slponline.com/product/620032--2014-v8-ss-1le-camaro-hood-heat-extractor.html#



Hines Performance too: http://www.hinesperformance.com/store/HEX-Vent-5GC-Edition.html



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Now keep in mind, from my reading, for any of this to be helpful and not just for show we would be touching on some Pratt & Miller type fluid dynamics/air management stuff...
I would figure there was plenty of work that went into the design of the V1 World Challenge hood and my guess is those vents were placed exactly where they were for good reason.
Doubtful any of us are getting that involved but I am going to try and mimic that WC hood as close as possible...
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I would love to see those Lumina vents in a hood! I think they would be the best for heat extraction and actually be the best ascetically pleasing ones of the bunch! in a weird way I also like the little side vent idea too. It would be very much like what they are doing on the new Buick models.

BDV
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Fast forward another few years... I will probably be drilling and cutting within the next week or so. Got things mocked up on the spare hood I picked up way back in 2014.





The tape stripe across the hood corresponds to the trailing face of the radiator fans. I laid a big sheet of thin (somewhat see-through) white craft paper that I picked up at an arts-n-crafts store on one side of the hood, then used a cardboard template of the Z34 vent to mark about where the opening would need to be cut into the hood. Marked the 4 corners on the hood on that side. I then made some alignment marks on the sheet of paper and the painter's tape, then flipped the paper over to the other side of the hood to allow me transfer the 4 corners. Using the reference marks on the painter's tape, plus some reference points on the hood itself (the corners of the holes for the washer nozzles made for convenient measuring points), I made sure both sides of the hood were the same. They're not perfect, of course - I'm just eye-balling all this with a tape measure and a Sharpie - but close enough for government work.

These initial openings are actually going to be smaller than the Z34 vents would need. My intention is to try to test the difference at the track. By making a smaller opening, I've got ~1/2" around the edge so I can drill some holes and bolt things in place. My plan will be to have flat plates (to block off the openings = stock hood), tripper fences (just a fence along the leading edge of the openings), and rough louvers (some aluminum sheet that I'll slice and bend to make ugly louvers to approximate the Z34 louvers). Should be fun to play with.
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I eagerly await your results. What does the other side of the louvers look like? Are there drain pans, etc to keep water from flowing directly onto the motor? I am repainting after I get back from Taiwan later this year and would like to do this before I send it to the shop. I'm glad someone is finally doing this!
If you look back to post #21, the Z34 louvers do have rain trays. However, as shown in that pic, when you flip the louvers to mount them the way I want to, the trays aren't oriented correctly. I'll have to figure something out for that.
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Put my new HF 4-1/2" angle grinder to use for the first time Friday after work, go the driver side opening roughly cut out. :cool:











Now that I've got the first opening cut, I have a better idea of what's going inside the hood. I knew there was an inner and outer skin, but I wasn't sure how they were joined together to provide support. The inner skin has kind of a giant golfball pattern to it (as seen here), with each of the dimples being about 6 or 8" in diameter. It appears that the peak of each dimple has that foam adhesive to bond it to the outer skin. Cutting the opening leaves big gaps:







My initial thinking is that I can cut a series of slots perpendicular to the edge of the opening, and then bend the inner skin up to meet the outer skin. Probably seal over where they come together with foil tape to make it "air tight" and prevent air from getting crammed into that gap at the trailing edge of the opening.
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Hi, can you post pics of the finished hood? I really need venting at the track and you're solution looks good so far. Thanks!
I also am waiting for the final results! Repaint time is quickly approaching as summer nears.
It's still sitting in the basement, unfinished. I want to do some before/after testing at a track event, but got lazy and never did it during the last couple events I got to in 2017. The holes I've cut thus far are actually a bit smaller than they will need to be to fit the Z34 louvers; I did it that way so I could do some experimenting, then enlarge the holes the rest of the way to fit the louvers. What I plan to do is make blank plates that will bolt on to cover the holes, and make some simple louvers with some sheet aluminum. That way I can test both configurations during a weekend at the track without having to trade out the entire hood.
No, 8 years (good Lord! 😔) after I started this thread the hood still sits in my basement, unfinished. Perhaps I can find time in October to get this first testing iteration complete, so I can put it on the car for an event at the start of November.
check out www.trackspecmotorsports.com for hood vents. We had the V at the track today and there is a race class Spec Vette and most had these hood vents.
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